Such a filtration filter device is disclosed in Japanese Unexamined Patent Application Publication No. 2007-304016 (Patent Document 1) and includes a filtration filter that filters an object to be filtered from a fluid, and a housing member that has an interior space in which the filtration filter is disposed. Fluid flows through the interior space. The housing member includes a disk-like base member and a case member that has a recessed portion defining the interior space on a lower surface side and a lower end portion that engages an outer circumferential portion of the base member.
In the filtration filter device disclosed in Patent Document 1, it is difficult to process engagement portions between the base member and the case member with high precision. Accordingly, a liquid can leak to the outside from a fluid channel through the engagement portions, or external gas can enter the fluid channel from the outside through the engagement portions. There is a possibility that an object to be filtered is adversely affected depending on the kind of the external gas.
One possible way to prevent such a leak is to seal a gap between the engagement portions with, for example, rubber packing. Such a solution, however, increases the number of components of the filtration filter device. In addition, when the object to be filtered is, for example, a biological substance, there is a possibility that the rubber packing will adversely affect the biological substance.
Accordingly, from perspective of improvement in sealability of the fluid channel, the existing filtration filter device leaves room for improvement.
It is an object of the present invention to solve the above problem and provide a filtration filter device that enables the sealability of the fluid channel to be improved.